OLED-Info discusses OLED glass with Corning

Corning recently announced the new second-gen Lotus XT high-performance glass suitable for OLED displays. The company has been supplying glass substrate and cover glass for OLED displays for years now. Now Corning was kind enough to participate in a Q&A session here on OLED-Info to better explain how they see the OLED market and what the future holds for Corning and OLEDs.

We talked to two Corning executives. John Bayne is Corning's High Performance Displays VP and General Manager, while Harrison Smookler is the commercial director and program manager of Willow Glass Substrates (flexible glass).

Q: Thanks guys for your time! Can you explain how Lotus Glass XT compares to the 1st-gen Lotus glass? What will be the advantages from the user perspective and from the manufacturing one?

John Bayne: Both glasses are part of the Corning Lotus Glass family, which makes them similar in many ways. They both offer exceptional thermal and dimensional stability, which means they withstand the high-temperature manufacturing environments required to generate OLED displays.

We developed Corning Lotus XT Glass to feature improved total pitch variation. For years the high performance display market focused on glasses with low compaction. Compaction is another word for shrinkage, and this shrinkage occurs when glasses are heated to high temperatures during the LTPS or oxide TFT manufacturing process. In truth, compaction is just one component to a more important attribute called total pitch variation. Total pitch variation is the shift in feature location that occurs between each glass sheet in the process, and it can be influenced by several factors beyond absolute compaction of the glass itself. Total pitch variation is very small, measured in microns or parts per million, but any variation at all can lead to lower yields.

Lotus XT Glass delivers even better total pitch variation performance. This results in better alignment throughout the TFT process, allowing panel makers to design panels with higher ppi, higher aperture ratios, brighter displays, and higher yields. Thus, there are clear benefits to both the panel makers and the consumer.

Q: Are there any products on the market that already use Lotus XT Glass?

In addition, two more companies selected the Corning Lotus Glass platform for their products. Corning and Century Technology Company (CTC) announced that Corning is the exclusive provider of specialty glasses for all of CTC’s LTPS manufacturing processes. CTC’s panels, featuring the Corning Lotus Glass platform, are currently in mass production.

CTC creates LTPS panels for its customers who subsequently use them in high-resolution display devices. CTC’s LTPS technology allows for vivid colors and bright pictures. Its panels feature more than 300 pixels per inch and are targeted at small- and medium-sized smartphones and tablet PCs.

Further, on Aug. 28, Corning and AU Optronics announced that Corning is an important and strategic highperformance display glass collaborator for AUO’s line of AMOLED panels. AUO selected the Corning Lotus Glass platform based on the glass substrate’s outstanding thermal and dimensional stability. This aids AUO with efficient manufacturing during the high-temperature processes that are required to develop its AMOLED panels.

There are several other panel makers qualifying Lotus XT currently, but these interactions have not been publicly announced.

John Bayne: Corning and Samsung Display’s equity venture – Samsung Corning Advanced Glass (SCG) – supplies OLED glass to Samsung Display, as well as for the broader Korean market. Corning and Samsung have a long history of collaborating in the display space. Corning works closely with Samsung to ensure they have the best glass possible for their LCDs and OLED displays. We cannot divulge specific plans or activities, but we can ensure your readers that Samsung continues to be a leader in the design and manufacture of OLEDs as well as specifying the most advanced materials required to enable these displays.

Q: Flexible displays based on plastic will arrive soon from both LGD and SDC. How do you see this competition to glass substrates? How does willow-glass compare to plastic (polyimide) for OLED displays?

Harrison Smookler: Corning does not comment on customer or competitor announcements. Any questions about specific capabilities or plans should be addressed to LGD and SDC.

Corning Willow Glass provides a very flat, smooth, stable, and optically clear surface for building sensitive electronic components. It does not stretch, scratch, or degrade when subjected to the processes needed to make high-quality devices.

These attributes are highly valued and will be increasingly critical as display quality, performance, and functionality continue to improve to meet high consumer expectations.

Efforts to mitigate the inherent limitations of polymer substrates for high-quality devices can result in compromised performance and added cost. Willow Glass combines the thin, light and bendable qualities of polymers with the inherent benefits of glass as a substrate.

Harrison Smookler: The timetable expressed by a Corning spokesman related specifically to roll-to-roll (R2R) manufacturing of displays, a low cost manufacturing technique commonly used today in the printing industry. Currently, display makers process sheets of glass of various sizes and are not capable of handling the spools of glass for R2R processing which Willow Glass can enable. New technologies and manufacturing techniques will need to be developed for the display industry to process Willow Glass in R2R format, and this is expected to take time. In the meantime, display manufacturers will still be able to utilize individual sheets of Willow Glass in their production process, so the availability of ultra-slim, light, conformable and/or flexible displays may occur well in advance of R2R processing, but again the development and commercialization timetables are managed by our customers.

While R2R processing for display makers may take some time, other potential applications for ultra-slim glass, such as touch sensors, have R2R processing today and the complexity and timing to incorporate R2R glass into those processes is expected to be much less complex and nearer-term.

Harrison Smookler: ITRI is a leading R&D organization that has been highly active in display and continuous processing technologies. We have a long-standing relationship with them that includes the hosting of a Corning Incorporated R&D group on their campus in Hsinchu, Taiwan.

ITRI and Corning have been working together since 2011 to develop the R2R technology for flexible glass.

Using ITRI's development experience on R2R processing of plastic substrates, combined with Corning's expertise in glass handling, ITRI and Corning developed specially designed R2R machines that produce functional touch panel modules on Willow Glass, a flexible display-grade glass substrate. This is the first ever instance of a glass based touch sensor being made on a complete R2R manufacturing line.

ITRI’s cutting edge R2R process technology using Willow Glass is capable of producing thinner and lighter designs that can be bent to a curve. This revolutionary combination of continuous processing and flexible glass will make low-cost processing of thinner and lighter touch modules, smart phones, tablet PCs, Notebooks, OLED lighting, solar cells and mobile touch-control devices a reality without sacrificing device performance and reliability.